Automatic tape dispenser

ABSTRACT

A device for automatically dispensing any desired amount of tape from a roll of tape is disclosed. A cutting mechanism in the device automatically cuts the tape which has been dispensed. A brake mechanism in the device prevents any further tape from being dispensed from the device once the driving motor is disengaged.

United States Patent 1191 1111 3,802,309 Bosland 1 Apr. 9, 1974 [54] AUTOMATIC TAPE DISPENSER 3,494,235 2/1970 Postolowski 83/225 3,237,595 3/1966 Kilham 83/922 X [75] lnvemorl James 30518, Wayne 2,695,057 11/1954 Krueger 83/649 x 3,710,664 1/1973 Eveland .1 83/205 X [73] Asslgnee' $23 23 fix 3,690,531 7/1971 Tanigami. 83/204 2,704,576 3/1955 Rosauer 83/221 [22] Filed: Apr. 17, 1972 I PP -z 244,840 Primary Examiner-J. M. Meister Related us. Application Data Attorney. g n or Firm-Darby and e y [63] Continuation-impart of Ser. No. 143,615, May 14,

1971, abandoned.

[57] ABSTRACT [52] US. Cl 83/176, 83/205, 83/399,

83/586 83/649 83/ 922 A device for automatically dispensing any desired [5 n 0' amount of tape from a roll of tape is disclosed A cut, [58] Field of Search 83/399, 400, 203, 204, ting mechanism in the device automatically cuts the 83/205, 221, 2251, 226, 230, 422, 587, tapewhich has been dispensed. A brake mechanism in 176, 922 the device prevents any further tape from being dispensed from the device once the driving motor is dis- [56] References Cited engagmi UNITED STATES PATENTS 1,870,800 8/1932 Elder 83/399 9 Claims, 10 Drawing Figures .JMENYEDAPR 9 m4 (802,309

FIGS

IO INVENTOR; JAMES M. BOSLAND ATTORNEYS PATENTEI] APR 9 i974 SHEET 2 0F 3 FIG 6 INVENTOR. JAMES M. BOSLAND W ATTORNEYS "ATENIEDAPR 9 m4 SHEET 3 OF 3 FIG.

AUTOMATIC TAPE DISPENSER This is a continuation-in-part of my copending U. S.

- patent application, Ser. No. 143,615, which was filed in the United States Patent Office on May 14, 1971,

now abandoned.

This invention generally relates to tape dispensing devices.

Tape dispensing devices heretofore available generally were of the type which required the user to manually grasp a portion of the tape, pull it from its roll and tear it across a serrated edge of the dispenser. In certain devices, dispensing of the tape from the device is automated to the extent that a lever isprovided which, upon actuation, causes a predetermined length of tape to feed out from the device. Even in these devices, it is usually necessary to manually grasp the dispensed tape and pull it across a cutting edge in order to cut it.

In the automatic tape dispenser disclosed herein, the dispensing of any desired length of tape and the cutting of such length of tape is accomplished wholly automatically.

Generally, the automatic tape dispenser embodying my invention consists of a housing in which the roll of tape to be dispensed is positioned in the housing rearmost from the housings tape dispensing end. The tape to be dispensed is guided over sets of feed rollers which are positioned forwardly of the roll of tape and which adhere to the underside of the tape. Upon being actuated, the feed rollers pull the tape forwardly. A set of stripping blades, positioned forwardly of the feed rollers, strip the tape from the rollers and guide the tape forwardly out from the dispenser.

In order to actuate the tape dispenser, a bar on top of the device is depressed. Depression of the bar causes energization of a battery-powered motor which drives the feed rollers forwardly and causes the cutter assembly to open to permit the tape to be dispensed from the device. When the desired amount of tape has been dispensed from the device, the bar is released. This causes the motor to disengage and the tape to stop dispensing. In the preferred embodiment of my invention, this causes a spring-loaded platform or lever earrying a scissor-like blade to rise upwardly to cut the tape against a shearing plate. In an alternate embodiment, the spring-loaded platform rises upwardly to engage the underside of the tape and hold it tautly against a roller positioned above the tape dispensing slot. A knife-point blade is positioned above the platform just rearwardly of the roller so that the rising tape is pierced and cut.

It is an important feature of this device that any length of tape can be automatically dispensed and cut by this device. The length of tape obtained from the device is determined by the amount of time the actuating bar is held in a depressed position. As long as the bar is depressed, the tape will continue to dispense. Once the bar is released, the tape is cut.

Another feature of this invention is that one or more ribs are positioned above the second set of feed rollers in order to guide the tape against the feed rollers and to insure that after the tape is cut, the leading edge of the uncut tape portion is not trapped behind the shearing plate or the knife-point blade. The ribs are arranged to crease the tape longitudinally thereby rigidizing it and permitting a relatively long piece to be dispensed without curling.

the 1 Another feature of this invention relates to a braking mechanism which assures that further tape is not dispensed from the device after the driving motor is disengaged. Upon energization of the motor, the output shaft and its associated gear train develop a degree of inertia which causes them to continue rotating for a short period of time after the motor is disengaged from its power source. This can cause a buckle to develop in the tape which may result in jamming the tape behind the shearing plate or the knife-point blade. To prevent this, a brake mechanism is provided.

These and other objects and features of this invention will be more readily understood and appreciated by reference to the following descriptions and drawings in which: I

FIG. 1 is a side elevational view partially cutaway of an automatic tape dispenser illustrating an alternate embodiment of my invention;

FIG. 2 is a plan view of the dispenser illustrated in FIG. 1 with the cover removed;

FIG. 3 is a partial cross-sectional view of the dispenser illustrated in FIG. 2 taken along the line 3-3;

FIG. 4 is a side elevational view partially cut away of the automatic tape dispenser illustrated in FIG. 1 during the tape dispensing operation;

FIG. 5 is a side elevational view partially cut away of a portion of an automatic tape dispenser which includes a second alternate embodiment of my invention:

FIG. 6 is a front view partially cut away of the dispenser illustrated in FIG. 5;

FIG. 7 is a plan view of the preferred embodiment of my tape dispenser with the cover removed;

FIG. 8 is a cross-sectional view of the dispenser illustrated in FIG. 7 taken along the line 88;

FIG. 9 is a front view of the dispenser illustrated in FIG. 7; and

FIG. 10 is an enlarged front view partially cut away and with the blade removed of the dispenser illustrated in FIG. 7.

Referring now to FIGS. 1-4, an automatic tape dispenser embodying my invention is illustrated. The dispenser includes a housing 10 within which a roll of tape 12 is rotatably mounted on a shaft 14. The ends of the shaft 14 are supported by parallel walls 16 and 17 extending upwardly from the bottom wall of the housing 10. The ends of the shafts 14 are seated in grooves 18 formed in each of the walls 16 and 17. A well 19 is formed in the bottom wall of the housing 10 to accommodate the lower portion of the cylindrical roll of tape 12 so that it is readily rotatable within the housing. A second well 20 (illustrated in FIG. 2) is formed adjacent the well 19 in the bottom wall of the housing in order to accommodate a spare roll of tape.

Forwardly of the position of the tape roll 12 in the housing, a set of feed rollers 24 is mounted on a shaft 26 which is rotatably supported by the vertically extending wall 16. The feed rollers 24 are driven in a forward direction by an electric motor 27 (illustrated in FIG. 2) whose output is connected to the feed roller shaft 26 by a suitable gear train arrangement (not shown). The gear train arrangement is positioned within box 28 (illustrated in FIG. 2). Gear trains of this type which connect the output of a motor shaft to a driven shaft are well known in the art and, consequently, are not discussed in detail here. A suitable gear train arrangement for this purpose is illustrated in FIG. 8 and described generally below.

The purpose of the feed rollers is to adhere to a length of tape 28, pull a further length of tape from the tape roll 12 and cause the tape to be fed forwardly out feed roller shaft 26 is a second feed roller shaft 32. A

second set of feed rollers 34 is mounted on the shaft 32. The second set of feed rollers 34 is positioned on the shaft so as to be interleaved with the first set of feed rollers 24. Thissecond set of feed rollers adheres to the length of tape that is fed from the first set of rollers and feeds that tape further forwardly to the set of stripping blades 36 which is interleaved with the second set of feed rollers.

The set of stripping blades 36 are generally rectangular in shape. They are held stationary within the housing by the first feed roller shaft 26 which extends through a hole in each of the stripping blades 36. The stripping blades remove the tape 28 from the second set of feed rollers so that the tape is guided forwardly toward the opening 41 in the dispenser housing 10. The stripping blades consist of relatively dull knife-edge blades which are vertically positioned. The narrowness of the blades contact area and their smooth, dull finish insure that the tape slides over the blades rather than adhering to them as with the feed rollers. To the extent described above, the preferred embodiment of my automatic tape dispenser and my two alternate embodiments are the same. I

In my first alternate embodiment, a generally U- shaped lever 40 is pivotally supported on a shaft 42 which extends through vertical wall member 44 and is supported in vertical wall member 16 and 17. A spring member 46 is wound about a portion of shaft 42 between the lever 40 and the vertical wall 44. One end of the spring engages a hole 48 in the lever 40 while the other end of the spring is rigidly fastened to the vertical supporting wall 44 so that the lever is spring-loaded upwardly to the position illustrated in dotted lines in FIG. I. An L-shaped portion 50 is formed on the front side of the lever 40. A platform member 52 consisting of a vertical member and a generally arcuate member is positioned on the L-shaped portion of the lever.

An arcuately-shaped cavity 54 is formed along the top portion of the lever 40. The actuating bar 60 for the tape dispenser is positioned above the lever 40 so that when it is depressed, it engages the levers arcuatelyshaped cavity 54. The actuating bar 60 may either be attached to the lever 40 or it may be held captive within the slot 62 on the top portion of the housing by enlarging its base portion so that its thickness is greater than that of the slot, as illustrated in FIG. 3.

The electric motor 27 is powered by batteries which are stored in the base of the housing. Since the electric motor is battery-powered, there is no shock hazard involved when the non-conductive actuating bar is brought into contact with the conductive lever 40.

In order to dispense tape from the dispenser, the actuating bar 60 is depressed. Depression of the actuating bar causes the electrically conductive lever 40 to pivot on shaft 42 so that it closes the open circuit between it and the electrical contact 64 positioned on the bottom wall of the housing. Closing the electrical circuit energizes the battery-operated motor 27. The electric motor 27 actuates the first set of feed rollers 24 and the second set of feed rollers 38 which cause the tape to be fed out from the tape dispenser housing at opening 40. When the desired amount of tape has been obtained, the actuating bar 60 is released. Since the lever 40 is spring-loaded upwardly by spring 46, release of the actuating bar 60 causes the lever to rise upwardly, thereby opening the electrical circuit and deenergizing the motor 26. As a result, the sets of feed rollers 24 and 34 come to rest and tape is no longer dispensed from the device.

In the first alternate embodiment of my invention, a laterally extending roller 68 is attached to a shaft 70 which is rotatably supported in slots 72 which are formed in an extension 71 of the vertically extending walls 16 and 17. The slots 72 permit the roller to move upwardly from its normal position which is illustrated in FIG. 4 to its uppermost position which is illustrated in FIG. 1, when urged upwardly by the platform member 52. The roller 68 coacts with the platform member 52 to hold the tape in a taut position.

A knife-point blade 74 (shown in dotted lines in FIG.

3) extends laterally across the front portion of the tape dispenser housing rearwardly of the roller 68. As previously mentioned, once the desired amount of tape has been dispensed from the housing, the actuating bar 60 is released and lever 40 is automatically urged upwardly. The platform member 52 in the forward portion of the lever engages the bottom side of the tape and urges it upwardly into engagement with the roller 68. As the tape is being urged upwardly, the section of tape just rearwardly of the platform and roller is pierced by the knife-point blade 74, thereby cutting the tape.

In the second alternate embodiment of my invention illustrated in FIGS. 5 and 6, a scissor-edge blade is positioned on the front portion of the platform. The primed reference numerals in FIGS. 5 and 6 designate elements which are the same as elements in FIGS. l4 designated by corresponding unprirned numerals. The description and discussion of those elements in FIGS. 1-4 is equally applicable to the corresponding elements in FIGS. 5 and 6, unless otherwise noted. A mating scissor-edge blade or shearing plate 82 (shown in dotted lines in FIG. 5) extends laterally across the upper portion of the housing in the same general position as the roller member 68 in the preferred embodiment. In this embodiment, when the actuating bar 60 is released, the scissor-edge blade 80 engages the bottom portion of the tape and causes it to rise upwardly into engagement with the upper scissor-edge blade 82 so that the tape is cut by a shearing action of the two blades.

Rib members 84 extending downwardly from the underside of the cover of the dispenser housing and positioned above the first and second set of feed rollers form a tape hold-down mechanism that insures that the tape portion does not become wedged behind the knife blade. The rib members also guide the tape to be dispensed against the first and second set of feed rollers and retain the portion of tape positioned over the feed rollers taut as the tape is being cut, as illustrated in FIG. I. Also, if the dispenser remains unused for a period of time, the tape would tend to lift up from the feed rollers. The ribs insure that the tape remains in contact with the feed rollers.

The preferred embodiment of my invention is illustrated in FIGS. 7-10. It is basically the same as the second alternate embodiment illustrated in FIGS. 5-6 with variations in the positioning of the motor, the shape and structure of the actuating lever, the structure of the tape hold-down mechanism, and the positioning of the motor contact switch. However, the preferred embodiment differs markedly from the alternate embodiments discussed above by the addition of an automatic brake mechanism.

As previously mentioned, when the actuating lever touches the electrical contact, the motor is energized and causes rotation of the feed rollers through a gear mechanism. This results in tape being dispensed from the front part of the device as long as the lever is touching the electrical contact. When the lever is released, it springs upwardly and cuts the tape which has been dispensed. However, because of the inertia built up by the output shaft of the motor and by the gear train, it has been found that the tape continues to dispense for a short period after the motor power source has been disengaged. This tape override has been found to be approximately a quarter of an inch. One problem caused by this override is that a bulge is formed in the tape between the second feed roller and the cutting blade of the device. When it is desired to dispense further tape from the device, the buckled portion of the tape may lodge behind the shearing plate and cause a tape jam. To prevent the possibility of this occurrence, a brake mechanism has been added to the device which causes the output shaft of the motor and the gear train to come to rest immediately upon disengagement of the motor power source.

The double primed reference numerals in FIGS. 7-10 designate elements which are the same as the elements in FIGS. l-6 which are designated by corresponding unprimed numerals. The description and discussion of those elements in FIGS. 1-6 are equally applicable to the corresponding elements in FIGS. 7-10 unless otherwise noted. Referring now to FIG. 7 in which the preferred embodiment of my automatic tape dispenser is illustrated, it is seen that the motor 74 is mounted on supporting wall 44". The gear train assembly 28" is positioned between walls 44" and 16".

Referring for the moment to FIG. 8, the gear train assembly 28 is illustrated in detail. A driving gear 78 is mounted on the output shaft 76 of motor 74. Driving gear 78 imparts rotation to gears A, B and C in the manner well-known in the art, and therefore not described in detail here. Gear C imparts rotation to gear 82 which is mounted on shaft 26" on which are also mounted the first set of feed rollers 24". Gear 82 imparts rotation to gear D which drives gear 85 thereby causing rotation of shaft on which the second set of feed rollers 36" are mounted.

The brake 86 consists of a long, rigid rod which extends from the rearmost portion of the gear train assembly to the front of the tape dispensing device. The brake is pivotally mounted on a bushing 88 which is supported between the walls 44" and 16". The width of the brake 88 is slightly less than the distance between the walls 44 and 16". A spring 90 positioned at the forward end of the gear train assembly biases the brake member upwardly so that the brake member portion 86A engages a brake drum 80 which is mounted on the driving gear 78.

Referring now to FIGS. 7 and 9, a generally U-shaped lever member 95 is pivotally mounted on the tape dispensing device. The lever 95 is composed of legs 94 and 100 and front portion 98. Lever leg 94 is pivotally mounted on a shaft 97 which extends through wall 44" and is supported by wall 16". A coil spring 96 is wound about the shaft 97 and is attached to the lever leg 94 at 99. The purpose of the coil spring is to bias the lever 95 upwardly. A generally rectangular platform 101 is formed at the juncture of the lever leg 94 and the lever front portion 98.

When it is desired to dispense tape from the device, the actuating bar (illustrated in FIG. 3) is pushed downwardly into engagement with the platform 101 on the lever 95. This causes the lever to pivot downwardly so that the lever front portion lowermost edge 98A first contacts the brake member frontmost portion 868 and then the electrical contact 92. Downward movement of the brake member 86 causes it to disengage from the brake drum so that the motor output shaft 78 and the gear train 28 are free to rotate. As the lever moves further downwardly, the lever front portion lowermost edge 98A engages the contact 92 which energizes the motor thereby causing tape to be dispensed from the device.

When the desired amount of tape has been dispensed from the device, the actuating bar 60 is released and the upwardly biased lever 95 springs upwardly out of engagement with the contact 92 and the brake member 86. Upward movement of the brake member 86 causes brake member portion 86A to engage the brake drum 80 thereby immediately braking the motor and gear train 28 to rest and preventing further tape from being dispensed after the motor power source has been disengaged, I

Referring again to FIG. 8, the brake member 86 is shown in its lowered positionin dotted lines and shown in its uppermost position in solid lines. The lever front portion 98 is shown in its lowermost position in dotted lines in FIG. 9 and shown in its uppermost position in solid lines.

A cutting blade 100 is attached to the rear surface of the lever front portion 98. The blade is adapted to cut the dispensed tape against shearing plate 102.

In the alternate embodiments described above, it was indicated that the ribs 84 and 84' on the inside cover of the dispensing device guide the tape to be dispensed against the first and second set of feed rollers and retain the portion of the tape positioned over the feed rollers taut as the tape is being cut. In the preferred embodiment, as illustrated in FIGS. 7-10 this function is accomplished by a blade-like member 1 10 which depends downwardly from a plate 112 which is pivotally mounted between support walls 16" and 17". The blade-like member is positioned directly above the second set of feed rollers so that the blade fits between an adjacent pair of feed roller wheels. In this way, the blade guides the tape against the first and second set of feed rollers and retains the tape taut as it is being cut. This also puts a slight V-shaped indentation in the tape which causes the tape to remain relatively rigid, for a time, as it is being dispensed. The inner surface of the top cover of the device bears against the pivotally mounted plate 112 so as to hold the blade in engagement with the tape. A series of such blades could also be positioned above the second set of feed rollers, if desired. The plate 1 12 is pivotally mounted so that in the event of a tape jam, it is relatively easy to rethread the tape betweenthe feed rollers and the blade 110.

While the principles of the invention have now been made clear in the illustrative embodiments, it will be immediately obvious to those skilled in the art that many modifications may be made in the structure, arrangement and proportions of the elements, materials, and components used in the practice of the invention, without departing from my invention. The appended claims are, therefore, intended to cover and embrace any such modifications, within the limits only of the true spirit and scope of the invention.

l claim: 1. A device for automatically dispensing tape from a roll comprising:

means for rotatably supporting the roll of tape; means positioned forwardly of said supporting means for adhering to the tape and pulling the tape forwardly, said adhering and pulling means being rotatably supported; motor means for imparting rotation to said adhering and pulling means; means positioned forwardly of said adhering and pulling means for cutting the tape; means for first actuating said motor means and then actuating said cutting means, said actuating means including a lever pivotally mounted for travel between a first position and a second position, means for pivoting said lever to said second position to actuate said motor means thereby causing tape to be dispensed as long as said lever is in said second position, spring means attached to said lever for returning said lever from said second to first position to cut the tape;

at least one blade positioned above the path of travel of the tape to urge the tape against said adhering and pulling means; said adhering and pulling means including a set of feed rollers, said blade being positioned between a pair of adjacent feed rollers, the lowermost edge of said blade being positioned below the uppermost edge of said pair of adjacent feed rollers thereby forming a generally V-shaped indentation in the tape. I

2. The device recited in claim 1, further comprising means positioned forwardly of said adhering and pulling means for stripping the tape from said adhering and pulling means.

3. The device recited in claim 2, wherein said stripping means comprise a plurality of blades which are p0- sitioned perpendicular to the path of travel of the tape being dispensed.

4. The device recited in claim 1 further comprising means for stopping rotation of said motor means and said adhering and pulling means when said lever means moves away from said second position toward said first position.

5. The device recited in claim 4 wherein said motor means includes an output shaft and a drum member on said output shaft and wherein said stopping means includes a brake member positioned beneath said output shaft, a first portion of said brake member being adapted to engage said drum member when said lever means moves away from said second position toward said first position.

6. The device recited in claim 5 wherein spring means are positioned beneath a second portion of said brake member in order to bias said brake member upwardly, said brake member second portion being positioned in the path of travel of said lever.

7. The device recited in claim 1 wherein said cutting blade is attached to said lever.

8. A device for automatically dispensing tape from a roll of tape comprising:

means for rotatably supporting the roll of tape;

means positioned forwardly of said supporting means for adhering to a side of the tape and for pulling the tape forwardly, said adhering and pulling means including a plurality of rotatably mounted spaced wheels, said wheels being positioned perpendicular to the path of travel of the tape;

means positioned forwardly of said adhering and pulling means for cutting the tape pulled forwardly, said cutting means including a cutting blade; means positioned forwardly of said adhering and pulling means for stripping the tape from said adhering and pulling means; motor means for imparting rotation to said adherin and pulling means;

means for first actuating said motor means and then actuating said cutting means, said actuating means including a pivotally mounted lever, spring means attached to said lever for normally maintaining said lever in a first'position, an electrical contact located at a second position which is spaced from said first position, means for pivoting said lever from said first position to a second position in order to actuate said motor and dispense any desired length of tape, said spring means pivoting said lever from said second to first position in order to cut the tape upon release of said pivoting means;

at least one blade positioned above the path of travel of the tape to urge the tape against said spaced wheels.

9. The device recited in claim 8 further comprising means for stopping said motor means and said pulling means when said lever means moves away from said second position toward said first position. 

1. A device for automatically dispensing tape from a roll comprising: means for rotatably supporting the roll of tape; means positioned forwardly of said supporting means for adhering to the tape and pulling the tape forwardly, said adhering and pulling means being rotatably supported; motor means for imparting rotation to said adhering and pulling means; means positioned forwardly of said adhering and pulling means for cutting the tape; means for first actuating said motor means and then actuating said cutting means, said actuating means including a lever pivotally mounted for travel between a first position and a second position, means for pivoting said lever to said second position to actuate said motor means thereby causing tape to be dispensed as long as said lever is in said second position, spring means attached to said lever for returning said lever from said second to first position to cut the tape; at least one blade positioned above the path of travel of the tape to urge the tape against said adhering and pulling means; said adhering and pulling means including a set of feed rollers, said blade being positioned between a pair of adjacent feed rollers, the lowermost edge of said blade being positioned below the uppermost edge of said pair of adjacent feed rollers thereby forming a generally V-shaped indentation in the tape.
 2. The device recited in claim 1, further comprising means positioned forwardly of said adhering and pulling means for stripping the tape from sAid adhering and pulling means.
 3. The device recited in claim 2, wherein said stripping means comprise a plurality of blades which are positioned perpendicular to the path of travel of the tape being dispensed.
 4. The device recited in claim 1 further comprising means for stopping rotation of said motor means and said adhering and pulling means when said lever means moves away from said second position toward said first position.
 5. The device recited in claim 4 wherein said motor means includes an output shaft and a drum member on said output shaft and wherein said stopping means includes a brake member positioned beneath said output shaft, a first portion of said brake member being adapted to engage said drum member when said lever means moves away from said second position toward said first position.
 6. The device recited in claim 5 wherein spring means are positioned beneath a second portion of said brake member in order to bias said brake member upwardly, said brake member second portion being positioned in the path of travel of said lever.
 7. The device recited in claim 1 wherein said cutting blade is attached to said lever.
 8. A device for automatically dispensing tape from a roll of tape comprising: means for rotatably supporting the roll of tape; means positioned forwardly of said supporting means for adhering to a side of the tape and for pulling the tape forwardly, said adhering and pulling means including a plurality of rotatably mounted spaced wheels, said wheels being positioned perpendicular to the path of travel of the tape; means positioned forwardly of said adhering and pulling means for cutting the tape pulled forwardly, said cutting means including a cutting blade; means positioned forwardly of said adhering and pulling means for stripping the tape from said adhering and pulling means; motor means for imparting rotation to said adhering and pulling means; means for first actuating said motor means and then actuating said cutting means, said actuating means including a pivotally mounted lever, spring means attached to said lever for normally maintaining said lever in a first position, an electrical contact located at a second position which is spaced from said first position, means for pivoting said lever from said first position to a second position in order to actuate said motor and dispense any desired length of tape, said spring means pivoting said lever from said second to first position in order to cut the tape upon release of said pivoting means; at least one blade positioned above the path of travel of the tape to urge the tape against said spaced wheels.
 9. The device recited in claim 8 further comprising means for stopping said motor means and said pulling means when said lever means moves away from said second position toward said first position. 